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POWER SIMULATION -- right_only_d0_5
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model: behavior ~ stim + day + stim:day + (1|rat)   (success COUNT; day within-window)
observed groups: stim n=4, control n=3   nrep=120, alpha=0.05
ground truth: stim:day=+5.31/day, rat SD=5.25, residual SD=9.96, days=6

 true stim:day interaction = +5.31 (100% of observed)
  N/group  | per-animal power | LME power
  ------------------------------------------
  3        |  0.38            |  0.80  <- observed
  5        |  0.82            |  0.94
  8        |  0.99            |  1.00
  12       |  1.00            |  1.00
  16       |  1.00            |  1.00
  24       |  1.00            |  1.00

 true stim:day interaction = +2.65 (50% of observed)
  N/group  | per-animal power | LME power
  ------------------------------------------
  3        |  0.11            |  0.28  <- observed
  5        |  0.28            |  0.40
  8        |  0.49            |  0.57
  12       |  0.72            |  0.77
  16       |  0.83            |  0.85
  24       |  0.95            |  0.97

Read the per-animal column as the honest power. At the observed N this study
is typically underpowered; per-animal power reaches ~0.8 only at larger N.